Cryogenic Foaming of Silk Fibroin Composite for Scaffolds in Bone and Periodontal Regeneration

Bone tissue has a remarkable regenerative capacity; however, advanced strategies are needed to support the repair process for critical-sized defects. While autografts and allografts remain the gold standard, their limitations have stimulated alternative approaches in bone tissue engineering, in search of scaffolds capable of mimicking native bone properties to promote effective regeneration. In this study, silk fibroin (SF)-based composite scaffolds incorporating β-tricalcium phosphate (β-TCP) and poly-ε-caprolactone (PCL) were synthesized using a simple and innovative cryogenic foaming method. The proposed fabrication technique overcomes many limitations of current synthesis methods, such as long processing times, the use of solvents, and reliance on complex, energy-intensive equipment. The composites were characterized using infrared spectroscopy to confirm the incorporation of all three components and their chemical bond arrangements. µ-CT, SEM, and ESEM analyses revealed that SF/β-TCP/PCL scaffolds exhibited great porosity and dynamic interaction with water while preserving pore morphology in wet environments. Swelling behavior, indirect cytotoxicity, and cell proliferation tests recognized the greater performance of SF/β-TCP/PCL scaffolds in promoting long-term cell proliferation, maintaining superior mechanical properties. These findings indicate that the proposed original, simple, and relatively low-cost manufacturing approach enabled the fabrication of scaffolds with excellent mechanical performances, controlled and stable porosity under both dry and physiological-like conditions, and high biocompatibility. The resulting constructs demonstrated promising results for cell proliferation and osteoconductive behavior, supporting their potential suitability as artificial bone substitutes.